In land seismic exploration work, geophones are mounted at spaced points along a length of leader wire and are connected to a multi-conductor cable that leads to a multi-channel recording device. For example, an individual section of leader wire might be about 150 feet long and have 12 geophones spaced therealong and electrically connected to its pair of insulated conductors. Each geophone includes a sensor that is contained in a housing which can be anchored to the ground by a spike on the lower end thereof. After the geophones are properly positioned and the leader wires connected up to the main cable, a suitable seismic source such as a charge of dynamite is exploded to generate acoustic waves which travel down through the earth and are reflected back upward when they encounter boundaries between rock strata having impendence differences. The arrivals at the surface of the reflected waves are detected by the geophones, which sends signals over the leader wire and the multi-conductor cable and to the recorder. The signals are used to construct a map of the underground rock layers, which is highly useful in the discovery of structures which might contain oil or gas.
To facilitate the collection and storage of the leader wires and geophones, so-called "D-Loops" have been used. Instead of coiling or rolling up a string of phones on leader wire which can result in a twisted tangle of equipment, D-Loops which are molded onto the leader wire about every four feet are hung on a hasp structure which resembles a large safety pin. In order to redeploy the geophones along a survey line, the hasp is unhooked and the field person while walking along the survey line permits the D-Loops to slide off of the hasp as the wire and phones are strung out.
In the past, the splices by which the electrical connector on an end of the leader wire was connected thereto were made adjacent the connector. Such splices were delicate and easily damaged in field handling, which caused a loss of signals from the entire length of leader wire on which a group of phones was mounted.
An object of the invention is to provide a new and improved leader wire splice to a connector assembly, such spline being combined with a D-Loop to provide a much more rugged and field-worthy splice than in prior splicing techniques.